YMF744B

2-2-1. DSP Command

The following shows the list of DSP Commands that are supported by the SB Pro engine. Both SB and SB Pro commands are supported.

CMD

Support Function

10h

o

8bit direct mode single byte digitized sound output

14h

o

8bit single-cycle DMA mode digitized sound output

16h

 

8bit to 2bit ADPCM single-cycle DMA mode digitized sound output

17h

 

8bit to 2bit ADPCM single-cycle DMA mode digitized sound output with ref. byte

1Ch

o

8bit auto-init DMA mode digitized sound output

1Fh

 

8bit to 2bit ADPCM auto-init DMA mode digitized sound output with ref. byte

20h(*1)

o

8bit direct mode single byte digitized sound input

24h(*1)

o

8bit single-cycle DMA mode digitized sound input

2Ch(*1)

o

8bit auto-init DMA mode digitized sound input

30h

o

Polling mode MIDI input

31h

o

Interrupt mode MIDI input

34h

o

UART polling mode MIDI I/O

35h

o

UART interrupt mode MIDI I/O

36h(*2)

o

UART polling mode MIDI I/O with time stamping

37h(*2)

o

UART interrupt mode MIDI I/O with time stamping

38h

o

MIDI output

40h

o

Set digitized sound transfer Time Constant

48h

o

Set DSP block transfer size

74h

o

8bit to 4bit ADPCM single-cycle DMA mode digitized sound output

75h

o

8bit to 4bit ADPCM single-cycle DMA mode digitized sound output with ref. byte

76h

 

8bit to 3bit ADPCM single-cycle DAM mode digitized sound output

77h

 

8bit to 3bit ADPCM single-cycle DMA mode digitized sound output with ref. byte

7Dh

o

8bit to 4bit ADPCM auto-init DMA mode digitized sound output with ref. byte

7Fh

 

8bit to 3bit ADPCM auto-init DMA mode digitized sound output with ref. byte

80h

o

Pause DAC for a duration

90h

o

8bit high-speed auto-init DMA mode digitized sound output

91h

o

8bit high-speed single-cycle DMA mode digitized sound output

98h(*1)

o

8bit high-speed auto-init DMA mode digitized sound input

99h(*1)

o

8bit high-speed single-cycle DMA mode digitized sound input

A0h(*1)

o

Set input mode to mono

A8h(*1)

o

Set input mode to stereo

D0h

o

Pause 8bit DMA mode digitized sound I/O

D1h(*3)

o

Turn on speaker

D3h(*3)

o

Turn off speaker

D4h

o

Continue 8bit DMA mode digitized sound I/O

D8h

o

Get speaker status

DAh

o

Exit 8bit auto-init DMA mode digitized sound I/O

E1h

o

Get DSP version number

Note:

(*1) The SB Block responds correctly to the commands for recording and also executes the DMA transfer. 80h is always transferred.

(*2) Only output is supported for this command.

(*3) This command only changes Speaker Status (D8h).

Undocumented commands other than the ones listed above are also supported.

February 3, 1999

-37-

Page 36 Page 38
Page 37
Image 37
Yamaha YMF744B (DS-1S) specifications Cmd, DSP Command
Page 36 Page 38

YMF744B (DS-1S) specifications

The Yamaha YMF744B, also known as the DS-1S, is a popular audio chip that emerged in the late 1990s, particularly known for its use in sound cards for PCs. This sound processor exemplifies Yamaha's commitment to delivering high-quality audio through innovative technology and user-friendly features.

One of the standout features of the YMF744B is its ability to support advanced sound synthesis methods, including wave table synthesis and sample playback. These technologies provide users with a rich audio experience, enabling high-fidelity sounds reminiscent of live instruments. The chip is also notable for its ability to emulate MIDI instruments, allowing musicians to create synthesized music that captures the nuances of traditional sounds.

The YMF744B integrates a 16-bit DAC (Digital-to-Analog Converter), which facilitates high-quality audio playback with a sampling rate of up to 48 kHz. This capability ensures that sound reproduction remains clear and devoid of distortion, appealing to both casual users and audio professionals alike. Additionally, the chip supports multiple audio channels, making it ideal for gaming and multimedia applications where spatial audio is crucial.

Another significant feature of the YMF744B is its support for various audio formats, including PCM (Pulse Code Modulation), ADPCM (Adaptive Differential Pulse Code Modulation), and even MIDI. The versatility in format support allows users to interact with a broad spectrum of audio applications, from game design to music production.

The chip also comes with integrated Sound Blaster Pro compatibility, which significantly enhances its usability with a vast array of software and games designed during the 1990s and early 2000s. This compatibility is crucial for retro gaming enthusiasts who seek an authentic audio experience with classics from the past.

Moreover, the YMF744B champions power efficiency, making it an attractive choice for mobile computing platforms. Its low power consumption means that it can be effectively used in laptops without significantly draining battery life, allowing users to enjoy high-quality sound on the go.

In summary, the Yamaha YMF744B (DS-1S) stands out due to its advanced audio synthesis capabilities, high-quality playback features, and compatibility with multiple formats. These attributes make it a favored choice in the audio processing domain, continuing to impact computer audio technology long after its initial release.
Top Page Image Contents